This invention relates to a window guard latch with an emergency release, and in particular to a guard latch having a release automatically triggered by a remote smoke detector or a hand held RF transmitter.
Guards are often mounted over windows to help prevent break-ins. These guards are typically made from metal bars, and are often embellished to enhance their appearance. To effectively prevent entry into the building, the guards must be secured against removal by would-be intruders. However, the guards pose a significant disadvantage because they also prevent exit from the building. Some local ordinances prohibit the use of window guards unless they are equipped with some type of emergency release. To allow emergency exit from the building, the guards are typically hinged at one side and some type of latch mechanism is used to releasably secure the other side of the guard to the window frame.
One type of releasable latch mechanism for securing a window guard comprises a lock box mounted to the building and having a receptacle for receiving and engaging a strike pin on the window guard. A release rod extends from the lock box through the building wall to the interior where it can be operated to release the lock mechanism. In some mechanisms the release rod is operated by turning it with a handle. In other mechanisms the release rod is operated by a mechanical push button. The push button can be provided with a safety cap with a finger opening facing away from the window to make it difficult to release the guard from the outside.
One of the inventors herein is also the inventor of a mechanical release latch mechanism disclosed and claimed in U.S. Pat. No. 4,258,504 which utilizes an armored release cable which connects between an exterior release mechanism and an interiorly mounted foot treadle for operating the latch mechanism. This design provides significant advantages over the mechanical releases of the prior art and represents a significant advance in the ability of an occupant to quickly and easily release the lock in any situation, including an emergency. This invention has been quite successful and has been adopted in many locales. However, while this device represents a significant advance, it is still desired to further improve and automate the release of window guards and the like for those emergency situations in which life threatening danger requires immediate action to exit the dwelling.
To solve these and other problems of the prior art, the inventors herein have succeeded in developing a window guard latch with an emergency release which can be automatically activated by a smoke detector, and which also provides for remotely automatic and manual operation by an operator. The latch of the present invention incorporates a manual, key operated release at the guard for local control, and an electric release which can be actuated by one or more of a number of means. A solenoid and trip hook operates the manual lock, and an RF receiver is combined with the solenoid to permit remote operation through the smoke detector as previously mentioned, in addition to a remote transmitter such as is typically used to open garage doors. In addition to operating the manual lock, the RF signal is also used to sound a local audible alarm to aurally alert the occupant of the fire. This provides additional time to the occupant to either exit the dwelling or even extinguish the fire. An important feature of the present invention is its battery back-up circuit which supplements the AC power circuit to ensure reliable operation upon failure of the electrical system in the dwelling. This battery is a Ni-Cad rechargeable battery which is continuously charged through the A.C. connection so that it is at full power in the event of an emergency. Furthermore, the lock of the present invention is constructed in modular fashion so that a simple installation can include a key lock manual release with electric push button release, and the RF link providing true remote control through the smoke detector and push button RF operator can be added on after the initial installation.
It is believed that the present invention is a significant advance over the prior art in that it provides immediate automatic release of the window guards upon a smoke detector's actuation in a simple, inexpensive design which can be readily installed in any home. It must be remembered that to a large extent these window guards and smoke detectors are often used in relatively inexpensive or crime ridden areas of a city and that elaborate systems of significant complexity and expense are not feasible for such an installation. This system is designed to overcome these problems and provide the maximum of safety and protection for the occupants of a dwelling with an absolute minimum of cost.
While the foregoing has been a brief description of some of the principal advantages and features of the present invention, a more detailed explanation follows.